Cross Talk Between Protein Kinase C and Intracellular Calcium in the Cardiomyocyte

蛋白激酶C （PKC）是多种亚细胞信号传导的枢纽酶之一，包括细胞生长、细胞分化和细胞运动。然而，PKC在成人心肌细胞中的作用尚未完全阐明。心肌细胞是利用钙作为快速细胞信号进行机械收缩和舒张的终末分化细胞之一。由于经典的PKC是钙调节酶，细胞内钙动力学的变化可能会影响PKC的激活。本研究通过荧光探针在体内测定PKC与胞质钙的浓度和分布，重点研究PKC与胞质钙的相互作用。我们开发了将它们的特异性荧光探针同时装载到单个肌细胞中，这些细胞在共聚焦显微镜的舞台上灌注。钙通过indo - 1可视化，PKC通过bobipy - phhor -acetate衍生物可视化。在缺血、肥大等不同病理生理状态下，PKC的激活随胞质钙浓度的变化已成为可能。我们还发现，在特定PKC亚型的组织学染色中，δ PKC激活是缺血预处理过程中心肌保护的关键因素。

Protein kinase C (PKC) is one of the hub enzyme of the variety of subcellular signaling which includes cell growth, cell differentiation, and cell motion. However, the role of PKC in the adult cardiomyocyte has not been fully elucidated. The cardiomyocytes is one of the terminally differentiated cells specialized for mechanical contraction and relaxation by using calcium as the rapid cellular signal. Since the classical PKCs are well characterized as the calcium-regulated enzymes, changes in the intracellular calcium dynamics might affect the PKC activation. This study focused the interaction of PKC with cytosolic calcium by using the in vivo determination of their concentrations and distribution with fluorescent probes. We developed the simultaneous loading of their specific fluorescent probes into the single myocytes which was perfused in the chamber on the stage of the confocal microscope. The calcium was visualized by indo 1, and the PKC was by a BOBIPY-phorbor-acetate derivative. Now it became possible to determine the PKC activation along with the changes of the cytosolic calcium concentration in various pathophysiological states such as ischemia or hypertrophy. We also found that in histological staining of specific PKC isoforms, delta PKC activation is the critical factor for the myocardial protection during the ischemic preconditioning.